The present invention is directed to a fastener. More particularly, the present invention pertains to a friction reducing coating or barrier between a fastener and a driver blade of a fastener tool.
Nailers and related fastening tools are well known in the art. Such tools are used in driving fasteners into workpieces. Such fastening tools may be, for example, pneumatic or combustion-powered driving tools for driving nails, staples, and other fasteners.
In fastening tools, such as pneumatic fastening tools, a driver blade is secured to a piston and reciprocates with the piston in a cylinder of the tool for driving fasteners into workpieces. Driver blades may be solid or hollow, and the driving surface may be of various shapes such as circular, rectangular, crescent, and other shapes. Generally, however, a driver blade for use in a fastener-driving tool includes an elongated solid body having a first end and a driving end. The first end is operably connected to a piston, and the driving end, having a substantially solid cross-section, contacts the fastener head when the tool is fired.
Fasteners, such as screws, nails, or staples, are positioned within the tool and with each firing, the driver blade contacts and forces individual fasteners out of the tool into the workpiece. The driver blade, in general, follows the fastener head in the cylinder within the tool, to the nose of the tool, and for a distance beyond the nose such that the driver blade is in contact with the fastener head for a period of time during firing. Unfortunately, because of the duration of contact and the amount of friction with the heads of the fasteners, the driver blade can become worn down or shortened after repeated use and must be replaced.
The driver blade may slip off of the head of the fastener as the nail is driven due to the angle of collation and tool recall, which subsequently wears the edge of the blade nearest the next fastener to be driven. As the driver blade wears in these instances, it reduces control of the nail. The nails may bend over when driven because of wear on the edges of the blade causing the blade to slide off the nail head.
Shortening of the driver blade is even more noticeable when the fastener is of the type which rotates as it is driven. The torsion or twisting forces amplify wear on the driver blade, as the fastener rotates at a high rate relative to the driver blade. Even after firing only a few fasteners, for example, driver blades can exhibit visual indication of wear on the driving end. At times, especially when fired into very dense substrates such as engineered or composite lumber, the nail head may have burn marks after firing when the fasteners rotate while being driven. These burn marks are indicative of the extreme frictional forces generated when driving a rotatable fastener into a workpiece that is more resistant to fastener penetration.
In addition, the driver blade may not wear down evenly; the driving end may wear down unevenly or in a lopsided fashion and cause the driver blade to impact the fastener head at a skewed angle or fail to fully seat the fastener. Such uneven wear of the driver blade may require a user of rotatable fasteners to replace the driver blade more frequently than a user of non-rotatable fasteners. Rotatable fasteners include fasteners in which at least a portion of the shank has a spiral geometry, such as a spiral shank fastener. Having to repeatedly replace a driver blade while at a work site can be time consuming and can increase labor costs and/or down-time.
The issue of driver blade wear is not widely addressed, and the few solutions that do exist involve using carbide-tipped driver blades. Even carbide tipped driver blades, however, may exhibit signs of wear when used to drive rotatable fasteners into very dense substrates.
It is well known in the art to coat the shank of the fastener with a lubricant to facilitate penetration of the fastener into the wood, and increase resistance to withdrawal of the fastener from the substrate. Such a lubricant is generally of the type that melts when exposed to high impact due to heat generated from friction, and quickly cools to serve as an adhesive after introduction into the substrate. Fastener shanks can be dipped or coated in polymeric material to ease or reduce the force necessary to penetrate the substrate.
However, lubricating the shank of the fastener does not sufficiently alleviate issues associated with driver blade end wear. In addition, while the types of lubricants used to coat a fastener shank, such as acrylics, facilitate penetration of the fastener into the wood and increase resistance to withdrawal of the fastener from the substrate, these are not as effective to reduce driver blade end wear.
Accordingly, there is a need for an apparatus and method that prevents or slows wear of a fastening tool driver blade. Such a solution would be economical and easy to administer or use without increasing worksite labor or time.